Note: Descriptions are shown in the official language in which they were submitted.
2~42~'7
THIS INVENTION relates to a particulate mixing
plant suitable for mixing ~ogether of mixtures of particles
of different sizes and/or densities optionally with the
addition of water or other liquid so as to makea resulting
composition having desired properties which may be put to a
particular purpose as may be required.
Generally the invention will be described in
relation to mixing plants suitable for formation ofa road
making composition but itwill be appreciated by those skilled
in the art that the mixing plant of the invention may be
utilized for prepration of compositions of particulate
materials useful for general industrial applications
such as in the food industry, building industry or in the
manufacture of detergents and lubricants.
Roads are constructed largely from naturally
occuring materials which include crushed rock and various
natural soils. The task of the roadbuilder isto turn a
heap of loose granular material into a solid load bearing
traffic carrying platform. For this to be achieved it is
necessary for particles of graded sizes to be accurately
spread and compacted to maximum density. It is normal for
materials to be brought to optimum moisture content before
their placement and compaction. This causes a reduction
in interparticle friction and allows the consolidation of
the materials to a solid bed.
In many instances the availability of suitable
high grade crushed rock materials is restricted. It therefore
is becoming increasingly necessary to make use of second
grade material and to improve their strength, alter the
plasticity of their fines and clay content or to alter
their water porosity characteristics by the addition of
suitable treatment agents such as cement, cement/flyash
blends or hydrated lime.
The above described material modification was usually
done in a fixed mixing plant or by means ofa tractor mounted
heavy duty rotary hoe or similar device.
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Also traditionally water has been added to
roadmaking materials priorrto compaction by means of a
water truck fitted with a spraying systemn Since the water
or moisture was added from the top down itusually affected
the distribution of the fines within the material and rarely
led to uniform moisteningO On the other hand the compact-
ability of such material is extremely sensitive to moisture
content and areas of inadequate moisture generally were not
properly compacted while those portions which were excessively
wet collapsed and lost dimension.
Non uniformity of material leads to premature
road failure~ It was not uncommon in the past for materials
to be spread in wide rows with graders and turned and mixed
with the graderblade repeatedly before they were able to be
properly spread and rolled. If road base materials are
accurately moisturised they are able to be placed with
modern high compaction paving machines thus eliminating the
needfor grader mixing and spreading. However, this has not
been the case previously.
Conventional mixing plants which have been used
previously for roadmaking in combination with a pavement machine
have comprised a loadinghopper for aggregate or road base
materials, an elevator or conveyor for transporting the road
base materials to a mixer wherein water was also added so
as to provide a composition which could then be compacted.
In this conventional mixing plant while it was mobile
in that it was supported by ground engaging wheels there was
no provision for the addition of filler or binding agent
such as cement, flyash or hydrated lime which acted to
stabilize the road making base compositions which included
tar, sand screenings or stones etc.
Another problem was that when the compositions
were transported by conveyor to the mixer they were open to
atmosphere creating a dust problem and also a certain amount
of loss of material until water was added to the composition
in the mixer.
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Also if filler or binding agent was to be added to
the roadmaking base compositions this would have necessitated
the use of a stationary hopper which would have had to be used
in conjunction with the mobile mixing plant previously
described. This provided a bulky and expensive system in
relation to manufacture of the roadmaking base compositions
prior to compaction.
It therefore is an object of the invention to
provide a mixing plant which alleviates the abovementioned
problems associated with the prior art.
The invention provides a mixing plant suitable for
mixing of particulate materials of different densities with
the addition of water or other liquid comprising -
(i) a receptacle for particulate materials having an
lS outlet;
(ii) a mixing station;
(iii) first conveying means including a conveyor belt for
conveying said particulate materials from the
receptacle to the mixing station and a gate member
associated with the outlet of the receptacle which may
be actuated to vary the gap or clearance between the
gate member and the conveyor belt dependent upon the
particle size;
(iv) a container for finely divided material capable of
acting as a binding agent or stabilizer for the
particulate material;
(v) second conveying means for conveying said finely
divided material to the mixing station;
(vi) means for adding water or other liquid to the finely
divided material and the particulate material at the
mixing station;
(vii) a collection station; and
(viii) means for transporting the mixed materials from the
mixing station to the collection station.
The receptacle for the particulate material may be
open topped and suitably may be V shaped or part conical in
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shape. It may include an outlet in a base wall thereof for
transfer to the first conveying means.
Preferably there is provided gate means which is
associated with the receptacle outlet for regulating or
controlling the particle size in the particulate material.
This may be of any suitable type and in one form may include a
gate member attached by link arms to a support axle which may
adjustably provide a gap or clearance between the conveyor
belt and the gate member which constitutes a preferred form of
first conveying means which is directly in the path of the
particulate material as it transferred thereto from the
receptacle.
The conveyor belt may have a drive roller at one end
and idler roller at the other and may be driven by any
suitable means.
The container for finely divided material or fines
may also have an open top and may have any suitable shape.
Preferably it has a much greater volume than the receptacle
and may also have an outlet in the base wall thereof for
transfer of the finely divided material to the second conveyor
means which preferably also comprises a conveyor belt of the
same type as described above for the first conveying means.
Preferably the container is supported by a plurality
of foldable support legs in the operational mode.
Preferably the second conveying means is such as to
feed finely divided material to the mixing station in metered
amounts.
The mixing station or zone may include a housing
which supports one or more shafts having paddles or agitator
elements attached thereto wherein the or each shaft may again
be ariven by any suitable means. Preferably the or each shaft
may include a plurality of radially oriented arms which
support the agitator elements.
Preferably the means for adding water or o-ther
liquid to the material at the mixing station may comprise a
spraybar having a plurality of jets wherein water may be
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sprayed into the material being mlxed. However, this may be
replaced in another form by a series of jets or holes in the
walls of the housing from which water may be conveyed thereto
from a water tank which may be separate from the receptacle
for the particulate material but more preferably may comprise
part thereof surrounding the interior of the receptacle.
The means for transporting the mixed material from
the mixing station to the collection station may be any
suitable type but preferably includes an elevator conveyor
having a drive roller and plurality of idler elements.
- Suitably the elevator conveyor may extend upwardly from the
mixing station to the collection station.
Preferably the elevator conveyor comprises two or
more sections pivotally attached to each other so that the
elevator conveyor may assume an extended orientation in the
operational mode and a retracted orientation in the
transportable mode.
The collection station suitably comprises a
container suitably having an inlet or open top and which is
provided with gate means in association with an appropriate
outlet which may open at predetermined intervals so as to
prevent or inhibit segregation of the mixed material so that
it may all be uniformly consistent prior to its end use.
Advantageously the outlet may be opened by actuating
means at predetermined intervals. Preferably the actuating
means comprises hydraulic ram assemblies attached to the
container of the collection station.
Suitably the mixing plant is mobile and to this end
the components (i) to (viii) above may be supported on a
single chassis having ground engaging wheels. There also may
be provided means for converting the mixing plant from an
operational mode to a transportable mode wherein the elevator
conveyor and the container for finely divided material may be
pivoted or moved from an extended position in the operational
mode to a retracted position in the transportable mode.
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Preferably the chassis may comprise a plurality of
support legs in the operational mode which are pivotally
attached to the chassis but which are folded thereunder in the
transportable mode.
Reference may now be made to a preferred emobdiment
of the invention as shown in the attached drawings wherein:
FIG 1 is a schematic outline of a mixing plant
constructed in accordance with the invention showing the
inter-relationship of each component thereof to each other.
FIG 2 is a side view of the mixing plant of FIG 1 in
the operational mode;
FIG 3 is a side view of the mising plant of FIG 1 in
a transportable mode;
FIG 4 is a perspective view of the mixing plant of
FIG 1 in the operational mode;
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FIG 5 is a perspective view of the mixing plant of
FIG 1 coupled to a prime mover and in the transportable mode;
FIG 6 lS a perspective view of the gate means
associated with the receptacle outlet;
FIG 7 is:a perspective view of the gate means
associated with the collection station;
FIG 8 is a schematic view of the drive means for
driving the various components of the mixing plant of FIG l;
FIG 9 is a side view of the mixing station showing
the agitator elements and their associated support shafts;
and
FIG 10 is a top plan view of the arrangement shown
in FIG 9.
In the drawings and in particular in FIG 1 there
is shown receptacle 10 for particulate material, wate:r
storage tank 11, outlet 12 of receptacle lO, conveyor ~ ~
belt 13 for conveying particulate material to mixing stat:ion
14, container 15 for finely divided material, outlet 16,
conveyor 17 ror transporting finely~divided material to mixing~ : ;
station or zone 14,:gate member 18, water spraybar l9 and ~ :
elevator conveyor~20 for transferring material to collection
: station 21.
In FIGS 2-3 thexe is shown also chassis 22 for
supporting the components described:ln FIG:l having ground
engaging wheels 23 supported on ground 23A. There is also:~
shown container support frame 24, support ties 25 interconnect~
ing container 15 and elevator conveyor 20, chassis frame
side member 26, support legs 27, support frame 28 inter~
connecting chassis 22 and elevator conveyor 20. ;~
In FIG 4 there is shown inlet 32~for container 15,~
inlet frame 33, hollow bag 34 associated with inlet 32 for
passing finely divided material into container 15, fixed front
prop legs 35 for container 15, rear prop legs 36 of container
15 pivotally attached thereto, support arms 37 of container
15 hingedly attached to chassis 22 at 38, hydraulic ram
assemblies 39 having telescopic sections 39A, 40, 41 and 42,
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water storage tank 43, dolly wheels 44, collection station
21 in the form of hopper ,45 having exit gates 46,
hydraulic ram assemblies ~7 controlling opening of gates
46, idler rollers 48 for elevator conveyor 20, conical
portion 49 of container 15, hollow legs 50 for dolly wheels
44 and hydraulic ram assembly 51 which controls pivotal
movement of hopper 45 and a rear portio of elevator conveyOr
20.
In FIG 5 there is shown prime mover 52 to which
chassis 22 in the transportable mode is attached and diesel
engine compartment 53. There is also shown support legs
- 27 folded underneath chassis 22.
In conversion from the operational mode to a
transportable mode as shown in FIGS 2-5, guy wires or ties
25 are disconnected and ram assemblies 51 actuated to
pivot collection hopper 45 and rear portion 54 of elevator
as shown from the position shown in FIG 2 or 4 to the
position shown in FIG 3. Rear portion 54 of elevator 20
is pivotally:attached to the remainder of the conveyor at
56. Support frame 28 is removed to enable pivotal movement
of rear portion 54 of~ conveyor~20.
In relation to container 15, prop legs 36 fold
transversely underneath container 15 in:the same manner :
as support legs 27 and prop legs 35 remain fixed to
container 15. Sections 39A, 40 and 41 of ram assembly 39
are retracted into base component 42 and container 15 tilted:
on arms 37 from the upright position shown in FIG 2 to the
horizontal position shown in FIG 3. Conveyor 20 also
comprises intermediate portion 55 and front portion 56A
which are pivotally interconnected at 57 and these portions :
are pivoted with respect to each other to assume the
attitude shown in FIG 3. Dolly wheels 44 are also
retracted into hollow legs 50.
In FIG 6 there is shown gate mechanism 58 compris-
ing adjustment handle 59, adjustment pin 60, adjustment
holes 61, bearings 62, axle members 63, interconnecting
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cheek plates 65 and 66, link arms 67 and 68 and gate member
69. Upon actuation of handle 59 and pin 60 engaging a
selected hole 61 gate member 69 may be elevated or lowered as
required to vary the gap between the gate member 69 and
conveyor belt 71. This mechanism is useful in -that it enables
the gap to be increased in the advent of larger particle size
or to be decreased in the advent of smaller particle size.
In FIG 7 there is shown collection hopper 45 having
exit gates 46, hydraulic ram assemblies 47 controlling
movement of gates 46 from a closed position shown in solid
- outline to an open position shown in dotted outline. This
movement is controlled by an appropriate timing mechanism (not
shown) to open at selected intervals to prevent separation of
the mixed composition. There is also shown hydraulic hoses 72
and rear roller 73 for conveyor 20.
In FIG 8 there is shown hydraulic motor 74
comprising fluid output 75 for drawing gates 46, fluid output
76 for actuating conveyor 13, fluid output 76A for actuating
conveyor 20 and a water pump (not shown) and fluid output 77
for driving conveyor 20. There is also shown gear pumps 64
for driving fluid through outputs 75, 76, 76A and 77.
In FIGS 9-I0 there is shown mixing station or
housing 14 comprising rotatably mounted support shafts 79
having radially oriented arms 80 having attached thereto
paddle brackets 78 having attachment apertures 78A for paddles
87. There is also shown retaining lugs 86 of each bracket 78.
Each shaft 79 i~ rotatably mounted in bearings 81 and there is
also shown meshing gears 82 and 83 rotating in opposite
directions. So as to drive shafts 79 gear 82 is attached to
output shaft 84 of motor or engine 85.
It will of course be appreciated that the mechanical
drive for the mixing housing 14 shown in FIGS 9 -10 may be
replaced by a hydraulic drive if desired and thus shafts 79
may be driven through hydraulic motor 74 if desired.
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It will be appreciated that the mixing plant of the
invention has many advantages in relation to preconditioning
or preparing roadbase materials prior to compaction, and thus
allowing roads, pavements and the like to be prepared
efficiently and inexpensively in combination with a pavement
or compacting machine. Designed to blend water and
particulate additives such as cement, lime or cement-flyash
blends with granular pavement materials it allows such
materials to have optimum moisture content and be mixed
uniformly.
Having a machine which can be quickly and efficiently
converted from a transportable mode to an operational
mode and vice versa, the mixing plant can be relocated and
set up allowing materials to be prepared at site prior to
placement.
The hydraulically self erecting container and levelling
legs described in the prefrerred embodiment and the working
support legs may be extended or retracted efficiently and
quickly. The same appliesto the foldable conveyor. The~
mixing plant requires no jacks or cranes and may be converted
to operational mode in a~matter of minutes. The cement
container 15 may be raised in position in minutes with
the telescopic hydraulic ram assemblies 39 and-the same
applies to the elevator and discharge hopper45. Water is
stored on board the machine as discussed previously and
has appropriate conduits (not shown) for delivery of water
to spraybar 19.
Diesel e~gine 53 may be connected to hydraulic motor
or pump 74 at one end and at the other andit may be coupled
via a clutch (not shown) and belt drive to the gearbox
comprising gears 82 and 83. In this latter form motor 85
may be omitted if desired.
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